MyJeep2000

Left side only... The reverse light, turn signal and even the flasher when I hit the key fob all work, on both sides...

It is just the brake and tail light on the left side. The top bulb...

I changed the bulb, the socket.. even the plate that the sockets twist in to.

I am at a loss.

Any ideas??

Noah911

If you’ve changed the bulb and your brake light still doesn’t light up, remove the bulb and check for battery power in the brake bulb socket with the brake pedal depressed. Use a test light or digital meter. Connect the black or ground clip to a metal ground and use the probe to check for battery power on each terminal in the socket while the brake pedal is depressed. If you don’t get power... I suspect you may not.

Then, you are supposed to check for power coming to the brake switch that is connected to the brake pedal arm. If you see battery power at the brake switch, but not at the socket, chances are you’ve got a break in the wiring in the harness that leads to this, the socket that is inoperable. You don't have to really do this part though.. because your other side brake/tailight is operating fine. That means the brake switch is getting and has power to it.

You will have to back probe and trace the wires in this circuit. Specifically, the wires leading to and backwards from the socket that is not working, to see where and why it has failed to provide this socket with power.

dave1123

Are you talking about a WJ or an XJ because there is a big difference. Quite often the contacts inside the bulb holder on the WJ get hot and relax their contact on the bulb. It can be checked by swapping the reverse bulb holder with the brake bulb holder. Either other one will work because the wiring is in the tail light assembly itself and all the holders are the same. When I had this problem, I used the reverse light holder to get the brake lights working until I got new holders from the boneyard. This is a common problem with the WJ if you sit in stalled traffic a lot with your foot on the brake. The reverse lights get used the least so the bulb holder is usually good.

I switched my brake/tail and my reverse bulbs to LED for this reason while leaving the turn signal incandescent so I wouldn't have to deal with the flasher.

The XJ has the same problem except you have to slice in a new socket.

MyJeep2000

My apologies. it is a WJ.. I need to change that in my profile.. I just noticed that. For what it's worth, I did change the socket as well as the socket plate.. So all of that is new. Admittedly it is kind of maddening.. You do all of that, and I look in the reflection (I was backing up to see the reflection in the glass of the building behind me) and the light still is out...

The marvelous temporary fix is the red LED light with the magnets that I can slap on the back when I am driving at night.. They use batteries... also wondering if I can hook a light up to the wire hook up that is wrapped around the trailer hitch... Just need to look at the connector... temporary, but at least it'll keep the bored cops in the one area near me from stopping me (again)... LOL

Noah911

I have an idea. It could probably work to get that light working again. The harness connector located behind the rear drivers side cargo cover has the wiring needed for this light. You can splice into the wire dedicated to correlate with this sockets light. Run that newly spliced in wire back to and behind your tailight cover. Hook this wire up to your new socket and hardware for this bulb. That would work if the socket etc is new and you know it to be good. I would still test the wire and make sure it is recieving power before splicing into and running it though... I think something like this sounds like it would work? I would still recommend verifying it with someone else prior to attempting to do something like this.
If you have the connection already at the reciever hitch for a trailer? If that's working, you can plug magnetic tow lights into it, and place the lights onto the back sides of your Jeep for the time being to get by for safety, and for preventing unwanted interaction with the authorities.

dave1123

Now that it was mentioned, there might be a fault in the harness behind that panel where the tail light connector is. I had my harness in my XJ go up in flames because of salt water from the road leaking in and corroding those connectors and shorting out my trailer tow module. Remember the brake lights are hot all the time.

MyJeep2000

Yeah, now the whole side is out... all three bulbs. AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

Noah911

It is just the one side.. I think you may need a whole new tailight assembly on that side. It sounds like the circuit board in the assembly has gone bad. They are not traditional sockets. There is a 4 position circuit board with contacts inside, with bulb holders that twist into that. This circuit board is built into the housing. If you hit and bang on it a little that may get the lights working for a moment?

You can replace these with aftermarket versions. The aftermarket ones wire directly to the sockets with no circuit board to break, instead of getting the OEM design.

dave1123

Okay.....My 2000 doesn't have any circuit boards in the tail light assemblies.

Noah911

Are they aftermarket?

Noah911

The second gen WJ from 1999 thru 2004 all use the same taillight, and they all use the same circuit board. OE Part number 55155139AH

dave1123

I've never seen it, my FSM doesn't show it in the circuit diagrams, and why would it be there anyhow? Besides, what is a "second gen" WJ? I'm not tearing it apart just to prove you wrong. Besides that, 55155139AH is no longer available from Mopar.

Noah911

I could of been more clearer.. A second generation Grand Cherokee, a WJ.

Part No. 923-036 from Advanced Auto is for just the circuit board, if you were wanting to try and replace that piece in the OEM tailight assembly too, instead of the whole assembly piece. It fiscally makes better sense to me to replace the whole assembly.

(edited to add):
Why would this be the method chosen by the engineering peoples to have made the tail light assembly in this way with a circuit board in it? Sometimes it just is... I suspect it has to do with easing of production though.

dave1123

Oh...a second generation Grand Cherokee, not a second generation WJ. You had me going there. I'd like to take apart my tail light housing and look for that circuit board, but my WJ is currently sitting at the shop awaiting settlement on my rebuilt engine's failure. It seems a brand new Melling oil pump sheared it's drive shaft resulting in spun bearings. 1200 miles on a new motor. Sucks!

Noah911

If you go try to take out the board, I bet you just break it all..... and will have to buy a new assembly!